Perhaps you should try some spelling variations:
cau thuc » cau truc, cuu thuc, can thuc
hanh vai » hanh vi, hanh tai, hanh van
hieu van » hieu va, thien van, lieu va
sach ty » sach y, sach tu, sach thu
hanh va » hang va, hanh vi
thuc va » thuc vat, thuc dan, thuc day
van cau » van dau, van hau, van chat
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cuu tre, cua triet
sac ky » cac ky, sai ky

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach ty) or (sac ky)) nang xa hoi. hieu van cau thuc va ((hanh vai) OR (hanh va)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ty) OR (sac ky)) nang xa hoi. hieu van cau thuc va ((hanh vai) OR (hanh va)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ty) or (sac ky)) nang xa hoi. hieu van cau thuc va ((hanh vai) OR (hanh va)) cua tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ty) or (sac ky)) nang xa hoi. hieu van cau thuc va ((hanh vai) OR (hanh va)) cua tre*.